a. Field of the Invention
This invention relates to pyrimidinylaminomethylenemalonate derivatives and analogs which are useful as anti-allergic agents, and to intermediates and processes for their preparation.
B. Description of the Prior Art
The Sterling Drug Inc. Lesher U.S. Pat. No. 3,320,257, issued May 16, 1967, discloses, inter alia, dialkyl N-(2-R.sub.2 -6-R.sub.4 -4-pyrimidinyl)aminomethylenemalonates where R.sub.2 and R.sub.4 are each hydrogen lower-alkyl, lower-alkoxy, lower-alkylamino, lower-alkylmercapto, phenylmethyl, phenyloxy, phenylamino or phenylmercapto. The compounds are shown to be useful as intermediates for preparing anti-bacterially active 5,8-dihydro-8-(lower-alkyl)-2-R.sub.2 -5-oxopyrido[2,3-d]pyrimidine-6-carboxylic acids.
The Dainippon Pharmaceutical Co., Ltd. British Patent Specification No. 1,129,358, published Oct. 2, 1968, discloses as intermediates for preparing antibacterially active 5,8-dihydro-5-oxopyrido[2,3-d]pyrimidines certain N-(2-R.sub.3 -6-R.sub.2 -4-pyrimidinyl)aminomethylenemalonates where R.sub.2 is hydrogen, a lower alkyl radical, a hydroxy group, a halogen atom, a lower alkoxy radical, an amino group or a lower alkylthio radical and R.sub.3 is hydrogen, a lower alkyl radical, a hydroxy group, a lower alkoxy radical, a lower alkylthio group or a radical of formula ##STR3## (in which R' is hydrogen, an alkyl radical, a cycloalkyl radical, an amino group, a hydroxyalkyl radical or an alkylsubstituted aminoalkyl radical, R" is hydrogen or an alkyl radical or R' and R", together with the nitrogen atom to which they are bonded, form a heterocyclic ring).